A cyclic process of peptide design, peptide synthesis, and peptide conformation study is used to refine methods of determining oligopeptide conformation in solution and predicting it from amino acid sequence. The principal technique for conformation study is high resolution nuclear magnetic resonance, coupled with model building. Circular dichroism, infrared spectroscopy and X-ray crystallography are also used. The peptides used in this study are chiefly synthetic cyclic oligopeptides and linear oligopeptides designed to fold into strongly prefered conformations other than helical. Transitions among stable conformations of some of these peptides are under study. Labeled peptides and amino acid derivatives are also prepared for nitrogen magnetic resonance studies of conformation.